Preheat oven to 375°F. Spray a 9 by 13-inch baking dish with cooking spray and set it aside. Cook egg noodles in a large pot, following package instructions, then strain and set aside.Add 4 Tbsp. butter to a large skillet along with diced onion. Cook on medium-high until the onions are translucent. Then, add flour and whisk until a thick paste forms a roux. Slowly add chicken broth and then milk, whisking until smooth and creamy, to form your béchamel.Mix in Italian seasoning and nutmeg, then shredded turkey, mushrooms, peas, Parmesan, and mozzarella. Season with salt and pepper to taste. Finally, add in the cooked egg noodles and gently mix to combine.
Add the mixture to the greased casserole dish and smooth it out into an even layer. In another pan, melt the remaining butter over medium-high heat and add panko breadcrumbs. Cook until golden, stirring constantly. Remove from the pan immediately and sprinkle them over the casserole evenly.
Bake for 30 minutes, until bubbling and heated through. Top with parsley for garnish, and enjoy!
Don't have turkey? Use a rotisserie chicken or boil 2 chicken breasts.
Dice the Onion: Make sure to dice the onion very finely. This should be a smooth, decadent and creamy cheese sauce.